On Tuesday 25 November 2003 10.39, Steve Harris wrote:
On Mon, Nov 24, 2003 at 08:21:55 +0100, David Olofson
wrote:
On Monday 24 November 2003 19.42, Frank Neumann
wrote:
[...]
I was wondering for a while when some older geek
will start
porting/rewriting e.g. the old Amiga's narrator.device for
Linux -
Actually, I was surfing around, looking for that a moment ago.
Can't seem to find any source code, though. (Didn't really expect
to.) Is it available?
IIRC if was partly hardware - possibly just the phonomes blown onto
a chip - but you could look in one of the amiga emulator packages.
I looked pretty carefully at the docs and schematics back when I was
hacking on the Amiga, and I never saw anything but the Paula chip (4
simple hardware DAC voices) when it comes to audio. I'm quite sure
narrator.device used only the standard audio output driver.
Yeah,
that's another though... I guess one way would be to
replace the synthesis stage of some current TTS system with a
chip emulator style synth. Or how about hacking a LADSPA or JACK
wrapper that generates control output that you can use to drive a
modular synth?
You can do fun things with formant filters (vowel peaks - theres a
dial that goes from A to EE) and envelope sequencers.
If there isn't a formant filter for LADSPA allready available
someone should make one - the tables of co-efficients are available
online.
I've seen some formant filter code somewhere... Can't remember if it
was a LADSPA plugin, though.
Anyway, formant filters might actually be a bit too sophisticated for
what I want to do. I'd prefer something more similar to speech
synthesis on old hybrid sound chips, like the 6581; that is, PWM, S&H
noise and possibly a simple resonant filter.
I've played some with *really* simple stuff, doing PWM on the PC
speaker, and it's not too bad. "Colored" noise for the plosives is
easy (PWM with random phase), and you can get a few vowels from just
pure PWM. Adding an LPF, or alternative waveforms might do the trick.
(A bit tricky to do with the PC speaker, of course, so I didn't try
it back then. ;-)
//David Olofson - Programmer, Composer, Open Source Advocate
.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,... |
`----------------------------------->
http://audiality.org -'
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